#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define PERMUTATION_SIZE 256

int grad(int hash, double x);
double fade(double t);
double lerp(double a, double b, double t);
void initPermutation();
double perlinNoise1d(double x);
double perlinNoise2d(double x, double y);
double perlinNoise3d(double x, double y, double z);
